The trip to the G8 summit at Camp David near Washington was to be the first foreign visit of his new term.

But he has reportedly told Mr Obama over the phone he is too busy forming a new government to attend the May 18-19 summit.

Prime minister Dmitry Medvedev will go instead.

With liberal and conservatives close to the Kremlin wrangling over cabinet posts and policy direction, experts say Mr Putin may be eager to show his domestic audience he is not weakened by recent protests.

"Foreign policy... will play the role of a servant to Putin's domestic agenda," said Lilia Shevtsova, an author and expert on Mr Putin.

"And his main goal domestically is to preserve the status quo and survive."

But being busy is Mr Putin's public reason for not attending. Some analysts suggest the move is aimed at sending a message to Washington.

Sending signals

Mr Putin has repeatedly expressed frustrations over US plans for a missile defence shield based in Europe and he has dismissed American criticism of Russia's treatment of opposition protesters.

"I think the signal he wants to send to America... is that agreements with America will be built on a balance of the strategic interests of America and Russia," director of the Carnegie Moscow Centre think-tank, Dmitry Trenin said.

"Russia will not make any unilateral concessions."

It is a message Mr Putin has repeated, from an inauguration-day decree on Monday in which he said Russia would demand US respect to a warning on Wednesday against modern-day violations of sovereignty, delivered before tanks and missiles trundled across Red Square to mark the 1945 victory over Nazi Germany.